Process of combustion and heat regulation and regeneration.



H. L. OHBRTY. PROCESS 0F GOMBUSTION AND HEAT REGULATION AND BBGENERATION. APPLICATION HLED APE.21,1911.

\ W w@ w# Attest: Inventor.

by M 0M Att) UNITED jerarca-Param ewigen.

zleaoc'isss orcoMB'rs'r'IoN'anD HEAT n'GULA'TIoN AND REGENERATION.

Speci-cation of Letters Patent.

PatentedJan. 5, 1915.

origina-rappntion sied March 16,1908, seriai N0.42i,5o3. Divided Vand this appiication'iiied april 21.

` ,911. serial No. s221549. a

To, allkioham 'it indy concern Re' tlmoirn that L Hrxiir L. DonnRTY, ga ci l. n of the United States of America, f .and aga sident of' the borough of Manhattan, ity,couiityfand State of New Yorkhhare oyente-d a certain. new and useful Process pinbustion and Heat- 4Regzgulati'o'n and i-generatioiu'of vwhich thel following isa 'fica-tion.

inre-ntion relates to a process of regu- .latairiflst'he te'iiiperature of combustion in a i-grasprodiicer furnace, andv of preheating .the-.air therefor;-and my invention relates i particularly to processes combustion, to .15: befcai-ri1ied'out in gas producer furnaces, .fiiihereiirwater' vapor isaised to keep down z -the1teiiiperature in the producer.

The. objects-of. myv img ention are the etli- -L ent,regulationA of the temperature in the reducer, vandl increasedeconomy of operalfthezlzgreater 'part of Athe vheat of' the gases 1ffroin.:t:he combustion` of the gas producer, faiidijtlie-@.ifaporization.of-lwater Aused in the ocessgiby xyasteheau insteadrof, as heretof siu'ni'i-rwfurnace in whielnthe tivo vare 'func' .3 0 ti'dnallylconnected'so-that:the gas from thc )rodi'i'cer is; biirned directly in the furnace v itfis formedi'andf'in which the products 'yi'fcombiistion can be. introduced at substantiaTllythe-'ten'iperature atwhich theyleave the furnace, into recuperators for preheat- 'i'ngtfhetir required for the'producer and for the eoi'nbust-ion of the gas, andfor the raporization of the water used in the process. As -a'paitilciilariillustration of apparatus in .S40 which'my' process may be carried out I have fis'elelcftedflaffurnace for heating. retorts for .theni'altng of illuminatingr gas-such' fur- "acisf being commonly termed frasbencheslf'l'iaeselected this type of apparatus for li''itlid ea'son that it furnishes ideal conditions for heoperation of thil process; but there 'lare a gi'ez'it many other well known types of. ffii'ruat in'coiiiu-ction with which my iii- .'yc-ntioucan'l be used \\'ith' .f freat advantage.

45.0 'lforf'ins'taiicm it can be eiiiploved in ,iras producers used ii. connection withf/.inc furA iiaccs` reheatincr furnaces. etc.

s set forth in iui' lafent No. $20,107, dated August 190C. in the operation of a gasiproduccr it is necessary to provide soria" ineans'for keeping down the temperature oniobtai'ned .1 /returning to the producer of the fuel bed iii the producer. The reaction onirhich the formation of producer gas principally .depends-'is that occurring when carbon is burned with a surply of airinsuflicient for complete combustion, namely,

This is a highly `exothermic reaction,- 4450 B. T. ULbeing liberated forevery pound of carbon burned. Accordingr to the process of my said prior patent, this excess of heat is absorbed by the endothermic lreaction nvolred in the reduction' of carbon dioxidv to carbon iiionox'id and the combination'of the liberated atom of oxygen 'with carbon h eahdiie largely to the fact that thevapori'Zation of the water has been'done either in' a separate boiler (requiring the combustion of fuel for the special purposerof vaporiiing such water),jor by heat-taken' fromthe producerv'itselfgvas .for example, by lpassingr the entering draft current of air over a body of water heated by the fuel bed in' the'j pro'- diicer, or by introducing air and waterinto the ash-pit of .the producer, the water'being converted into steam by absorptionof latent heat taken from the fuel' in the producer it-. self. There is, broadly speaking, no loss of lie-.it in the. system diie to dissociation of steam in to its elements, .the heat absorbed in dissociation being returned to the cycle in the subsequent recombination ofthe elciiieiits-iu the furnace. So far. as the produrer is 'c onceiiiial. vt-licretore, here 1s no loss ot' heat diie-to the introduction of steam iiio the producer sare vthat vrequired to heat the steam from the temperature at which it is introduced to that at which the, Waste gases leave thefuriiace: and this loss is 'onli' serious when the Water' vapor or steam is siippliei'lfin such quantity and the tem- .peifaturefof-tlieprofluce is so low that a lzirpgeproportion ofit goesthrough the producer "iuiideroiuposed..-v Butv .if the water mustfbe rapoi'if/.ediinto steam by heat taken 'directly from the fuel in a boiler, or in any otherway than by the utilization of otherv. isc wasted heat, a considerable loss, which may be avoided by the means herein described. necessarilv results.

Ordinarily, in producers operating with a draft current of air and water vapor or steam, the air has been supplied to the producer with little or no previous heating. It is clear that the heat absorbed in heating this air up to the temperature at which the waste gases are discharged, is so much heat abstracted from that which the producer is capable of converting into useful potential' heat in the producer gas. In the great majority of cases where producer gas is applied to the heating of furnaces, etc., the products of combustion leave the apparatus at a teinperature above 1000 F. Even where recuperators are employed to conserve part of this heat carried out of the furnace, the temperature of the waste gasesis seldom reduced below 800o F.4 If the air enters the reducer at 60 F. this means, even when t e'waste gases are reducedl to 800 F., a loss of over 2500 B. T. U. more or less per pound of carbon gasified in the producer.

Assuming that the waste or fiue gases leave the furnace at a temperature of 10000 (which is a much lower temperature than is gener'- ally obtained even when regenerators are used) there is a loss of sensible heat in the gases of 3135 B. T. U. more or less. By the method herein described and illustrated, I lutilize a large part of this heat of the Waste gases to raise the temperature of the secondary air and also to raise the temperature of the primary air and to vaporize water, the resulting steam being mixed with such primary air; andV I am thus enabled to return to the producer thev greater part of the waste heat in thev products of combustion and thereby I greatly increase the economy of operation and the efliciency of the apparatus. The vaporization of the water and heating up of incoming draft currents being no longer required to be done to any considerable degree by heat derived from the producer itself, a greater -proportion of strain may be dissociated in the producer and therefore a greater proportion of the lheat generated in the producer is returned to the cycle by the subsequent recombination of hydrogen and oxygen in the furnace; also the calorifie value of gas issuing from the producer into the furnace is higher.

It is important to superhcat the water vapor to a high degree, to facilitate its deceniposition in the producer; and it is also irnportant to mingle the water vapor thoroughly with the lair; and furthermore it is particularlv desirable to conduct the evaporation of the water in connection with the .heating of the air and during the earlier stages of such heating, for during such evaporation the consequent absorption of latent heat keeps down the temperature to a relatively low point, so that there is a relatively great temperature-difference between the air and waste gases, the latter already cooled considerably during their.t passage through the upper sections of the recuperator, so that a relativeiy larger proportion of contained, heat is abstracted from the waste gases than would be the case ifthe evaporation were done after the air had already been heated to a high degree. In other Words, by doing the evaporation of the 'water by waste gases which have already parted with a large proportion of their heat in superheating the Water vapor to a high degree and in heatingthe air to a high degree, heat isntilized efliciently which would otherwise be relatively unavailable, owing to the relatively low temperature of the waste gases. It`is obvious that there cannot be an efficient interchange of heat between relatively cool waste gases and a body of water when the latter is separated from the waste gases by thick metal Walls, such as are necessary when the water is evaporated in a boiler set into the recuperator. This difficulty I avoid, according to my invention, by providing the air passages of the recupera` tor with water-supply means, so that the air in ssing through these passages itself evaporates the Water, taking up the water l vapor as fast as formed and so greatly facilitatin'g the liberation of more vapor, and also keeping the air relatively cooland relatively moist lnthe early stages and so in a relatively good condition to take up heat from Athe already partly-cooled .waste gases. The

absorption of the water vapor as fast as formed by the air results in'a particularly 105 thorough admixture of the air and water vapor, which is particularly favorable to efficient action of both in the fuel-bed of thel producer.

Referring now to the accompanying draavings showing a gas bench adapted for the carrying out of my process, Figure 1 shows a vertical transverse section, looking from the front, on the line AkB of Fig. 2,. and Fig. 2, represents a longitudinal section on the irregular section C-D of Fig. 1.

The drawings represent a single retort furnace or bench with its gas producer. In practice the benches are always bui lt together in groups or batteries, two` benches being placed back to back forming a twin furnace or bench setting. Any number of these twin benches may be built together side by side. For the purpose ofillustrating my inven-y tion, however, itis suflicicnt to represent 12-I simply a single individual bench.

In the drawings 1 designates the gas producer having a grate 2 for supporting the fuel bed cf the prrducer. The fuel may either be coal, or coke remaining from the 13 deplh. a bol oi ignited fuel being' allow thiS lied el' a rea. AS 1s usual in producer practice. the lepth oi the fuel bed is.y generallv. ernsnlefalile. Since by using' a Qonsulerable delith et' ruel :l gas 0i' much better and u-fu'e init-'irai qual'tvis secured.

The air .for thexpartial combustion uhieh tahesi pl: in the producer, if; admitted through jwits 5 under the grate L. which port uoinnuuiieate by a pas: ge er flue G with the upper lrngitudinal llue 7 et the priniary recuperator 8.' This primary re- Cug'mrator eoxnprisea a aerien of tlues 7 within which are other fines (usually metal pipeal 1l.. thriv ugh which a portion of the products ol' cenibufztion from the furnace paas in escaping to the stack. The primary air to l-e heated enters'the lowermest of the flues 7 through a suitable damper or register lll. and thence passes upward through the various fines 7, and around the heatinfr flues Y1].eaehflue 7, except the last, being eonnected tu they flue 7 next above it, thel een nectirns bring altmnately in frontand in rear, so that the ues 7 in principle forni a return bend passage for the air. 'The various heating?y pipesA 11 are likewise connected in series so as to ferm in principle a returnbend heating coil. The uppermost of the fines 7 is connected to the passage (i. ln several of the lower fines 7 are `vater pans 13 provided with overflow connections 1.4, whereby when the Water level in any pan rises above the level of such. overiiow oon-- nertion the Surplus passes tlnough such overllo'a connection, over the heatingr pipe ll below, to the. pan beneath and so until the laat pan is reached. The overllow connectirns of this last pan connect with a Waste pipe 16. These pipes over which the water drips may be provided on their under sides w ith transverse ribs to prevent the water from traveling endivise. on them.` and so dropping mainly from one end or the other of the pipes. It is of course desirable. that the l'all of the water 'lrlrui the pipes` shall be;jt`airly uniform. In ease there is reas( n to believe that at times nioiature coni municatrd to the air during ita` passage through the fines; 7 by the evaporaticn oi the viator in Said pans, niay nft le. nuliieient tbor the purpose desired. an auxiliaryrv steam supply may he provided.y 'lor o'i'aniplr. a gfteani pipe l?. opening into one of the lines i. 'the louernirst of the pipea` il communiealw :i an oll'take flue l5. 'the uppr-r naat ot' the pipes ll cf'nneets with a line l?, preleva. y rl refractory material. havine poil :"ll leading into the tornare or `i r `"-iainlrm 2l vmithin whirh arf. tlv .--mab The h-'t i.' in austfm naaien from tins furnace, 2l ente;`

rthe Hue i9 at or above 2000e F. usually. and

during their paasage downward thr( ugh the reeulierater S. they give up a large part of their sensible heat to the entering air rurrent Surrounding theni and [lowing upnard in a direetilfni the reverse ol' the downward llow ot" these produets of combustion. Such enteriluf air current 'therefore hiafhl)v heated and returns to the producer a large part of the eenaible heatI of the. produrte, otl eonibustirn which would otliervviee lle lost. A further portion of the heat of thaw products of combustion la utilized in the, evaporatimi of water in the paneY 123 and of moisture pic-lied up by' the air current: all of the water carried by the air current being' therefore converted into .str-ani which usually is highly suporheated bv the time the. air has passed through outlet I into the ash pit. By these two methods; oi' al'ieorbing and utilizing the Waste heat of the portion of the prrducts of eombustirn paasingthroiurh thel reeuperator 8, a very large pimiortion of the available heat of Such wagte grasas is utilized.

It will be apparent that nrt only will the water vapor be mixed most thoroughly with the primary air, but that the proportion of Water vapor to air will 'ne practically ernsstant so longas the feed rf water or steam to the compartments of the primary reeuperator is conrtant; also. that the. proportion of water vapor to the air may be varied Within wide limits, by eupplying: fater to more or les@ of the pans lil. ln this vvay the proportirzn of water to air may be varied so that the .steam highly superheated after having the reeumrator. or that the air is merely Saturated. or that it carries a la rge excess ri' water, 'lll'ierelrv the temperature in the producer may he regulated as desired.

The secondary reeuperator l), upon the opposite sides of the furnace. comprises, in its upper part. llues 23. preferably of refractory material. and. in its lf-wcr part. billes 24. PreferablyY of" metal. These lines 25! and 24 are located in a vertical llue lt will be understord that. as is efunnon in reeuperator practicar. the Hue@ '93 aud 2lare connected end to end to forni a, return lend conduit. l do not vfurther illustrate the u nstrurtion el' thin Serf-indary rocuporatl r fl. as the prinriple of Hugh rreui'ierator is ivell undurstud. and Since the .Caid ief culierat-r is tullvillustwitefl and l etui-ilI eil in in v lateut No. 992.322. dated May llll. ol" which this present application a di\ ision.

ln the serfmdarv recuperatiin il, Secondary air is heated in panning vertically through the llue 25. bv contact with the lines lil and Ll-l. through which l'irodurts of rondan l' lnrnaee chamber ..f'l paas :farfelu 1-,.onf.;lary air ao heated passes through fiues 28 to nostrils 29, there encountering combustible gas rising from producer 1, causing the combustion of such gas within chamber 21 and ai'ound the retorts ,5 "4:5,ionc part of the resulting products of combustion passing out through recuperator 8 and the other part passing outward through recuperator 9, as above described.

Heating the primary and secondary air 10 by separate currents of products of coinbiistion, passing directly from the furnace chamber 21 into the primary recuperator, and secondary recuperatoi', respectively, has numerous advantages over the common hitherto-prevailing practice where both primary 'and secondary recuperators are used, according to which former practice the primary recuperator is heated by furnace gases which have already passed through the secondary recuperator and have parted therein with much of their heat, and therefore reach the primary recuperator at a relatively low temperature as compared with the temperature at which the furnace gases enter the primary recuperator, according to my invention. Ln such former apparatus in which Water vapor isadded to the primary air, such water vapor has usually been evaporated in a separate boiler by a separate source of heat, or else such water vapor has been obtained by evaporation from a. pool of water in the ash pit, the evaporation from such pool being due mainly to the heat of cinders dropping from the fuel bed,

and to heat radiated downward from the,

fuel bed. It will be clear that in such former apparatus the water vapor supplied to the fuel bed in the producer is in no sense proportional in amount fo the amount of air s passing through the primary recuperator;

and that the proportion of water vapor to primary air may vary greatly and undesirably; also such water vapor carried by the primary air into the fuel bed can have received little or no superheat before reaching the fuel bed, and the primary air will in turn be chilled to nearly the boiling point of water in passing over the pool of Water in the ash pit. In my process, however, the

5 proportion of water vapor to air will be practically constant so long as the feed of water or steam to the compartments of the primary recuperator is constant; also the proportion ofwater vapor to air may be 5 varied within wide limits, in my process,

by supplying water to more or less of the pans 13, or by regulating the flow of steam through the steam inlet 1T. In this way the proportion of water to air may be varied so that the steam is highly supcrhcated after regulated 'as desired, and as niay be required, with different kinds of fuel, to limit the temperature of the fuel bed so that clogging of the fuel bed by slag may be avoided.

A further advantage of admitting water or water vapor to the initial or low temperature stages of the primary recuperator, and of heating this primary recuperator by an independent current of products of combustion taken directly and at high temperature from the furnace chamber 2l, is that there is a greater temperature difference available for the transfer of heat from such current of products of combustion to the primary air, than is the case when the products of combustion for the primary recuperator pass first through a secondary recuperator before reaching the primary recuperator. Transfer of heat from one body to another takes place at a rate which, in general, is proportional to the difference in temperature of the two bodies. If the difference in temperature of the two bodies is low the rate of transfer will be low. From this it follows that, if the products of coinbustion for heating the primary recuperator have already parted with a large part oftheir heat in a secondary recuperatcr.l b efore reaching the primary recuperator, theii temperature by the time they have reached the primary recuperator will be so low thai the transfer of heat from such products of combustion to the primary Iair will talc. place somewhat slowly and therefore the primary air can take relatively little of the heat from such products of combustion, as compared with the heat which the pri mary air takes from the products of combustion,lin an apparatus operating according` to my process herein described.

The net results of my process are, that I ain able to control the temperature of the fuel bed in the producer 'with greater certainty by being able to evaporate, by waste heat alone, a greater proportion of water than is possible when the water is evaporated by contact of the primary air with the water in the ash pit and by radiation of heat from the fuel bed in the ash pit; that the proportion of water vapor to primary air remains practically constant for any one adjustment; and therefore I am able to use without slugging, coals which could not well be used in former apparatus because of the difficulty from slagging. heat employed for evaporating the water is not drawn from a separate source and therefore produced at a separate expense, nor is it drawn from the fuel bed itself', but is heat that would otherwise be wasted.

For the production of a high proportion of carbon monoxid, it is essential that the fuel hed shall be maintained at a high temperature; yet when using American coal, exceeding a certain temperature close to that at which it is desired to maintain the fuel F urtherinore. the

lieil. will more ciirfsiio formfition of Plinlm ii. lili riwiilliiig 51:1 is-zisii oll fiiel :mil lios Viililoroiiiiili'tis ringing of' the producer. Whoo lliil iiriiiirzry air iiiifhs up ihr Waiter i viii/ir :wily ii'hilr 'passing through (he :ifih iii, ii i 'iiii'iossililo lo Iiiiiiiilziiii :lowly ihe iof iriil iorti n of nii' :mil miiloriieiiiiir i ilu; iiii'iinriY alriift mi i iiriiiriiiii-iiii of iiliriioiliiiffr h ihr iviirr Vapor :iililcil vzii'li siig'eii of lha rociiiiaiiiilor iiwll', 'i' proiriis :i nire rogiihii'ioii of the proi--iiioii oi miler uiiior und the iligrie of ihfzil (easy to :ittiiri :ii/iol il; is en y Lo iir-.iiiziiii thru: i'iroiiiortionf's prmgtiriiily coiwtziii'i so that for these rfinSonS it is :imite iwriiiigsihlu, in my producer, to keep the limi huil much ncnrir the Cliiiliering point liiiiii wohl-l lie permissible Lithrwi i. This iti i# iii-.ii'ticiilarly irriportzmt; for the reason that their. is si, critical temperature, which, if iigl'itiy oxcveilerl. results iii, 1i greatly inl VVirlrl of l'lie rfirlioii riioiioxiil. Bilt t' 'iiicfil teniporiitiirc close @o alle ging" point of xiiiiiiy iimrii'iin Cooler. for ii hir-li rmisrn it lifii-t heen iniiziossilile, without lie niii regulation of the proportion of air lo Miter permitted 'oy my iiiotliod zilioi@ diesviil'ieii. to exineil this @riti-sail emiiircrtiire, il lim Filililii! fuel Such :isi referred to it, l cleiim is:- l" `ii (hir-crilicd process which wmp: .i iig` fi Llrnlil. mirra-m1 of mixed water wiper .i ii hosted air tliriigh a lied iii ol' fiivl of ei'l'cfiiic giiifi g i'lvpth in a guai producer; mixing; with the resulting prw (hiver gag lifaziirrl iiir iiirl liiii'iiiiig the gus iii :i furnace chaii'ihuny and dividing the resulting proiliiwts of coirilsiisition iol/o tivo ciir- 40 rents, proheiitirig air ior ihr: droit eiiiiiply of ihe riroliiii'er by the limit 'il ne of saiiil Cil@ rents, c-Vzipriiratiiig moisture liv the lient of .QiiCh current, while` :Iiiifli iiioiistiirf ifi iii hout trz'irisferring i'ilsiiioii to he ziir heated by l the :ifiii'ie ciu-rom?, 51ml mingling Lili? wiiter iiipor so profliicefl with siii'li :iir :iiiil tlirrr by maintaining. lirtweeii Siivli nir mid siifsh ifiirrciit. a relzitirilif great (lill'crreiiffii of teiniiciniiii'e, :ind prliifsiting :iir tor coiriliiiiqtion 50 with Lliff producer gris by lient of the otil'irar of f-ziifl ciiireritfi.

i The herein describe-(l proceiss which ,iiiprisrs passing through ii lied of fiiel in .fi ggfiS Vproducer. fi lioiil'vd priii'iiirf: Clirreii, of iiiixwl nir :mil wat vapor, ii'iiiigliiig with the gais so prodiicml` :i hunted siiifondiiry ciirreiit, of aiir. liiirriiiig the mixture in fi fiiriizico rliiiiiilwr iiiinl lli limi the ri oi' ioiiil i lion into (im cixrri'ints.y :rml on, iria'` mill ciiiri-ii'itfi liroiigijli Sopnriite rcciiijierfitois ohr for thii iirizirv current :iriil the other for i'lic Secoiifzirv current. 51ml siiiiiily ingr nir nml ,iii-oi :iris for ih@ primfirv our rent to the ririmziiiif reciiperiitor amil nir for 65 the secoiiiliirlif current to the scoiidiiry re- Huiting proaliioi cipemuiir, Airifl highly @iiiiii-lioziiiiig the ii'iiier moor -tiipiilii cl lo lili@ iiriii'iiiri iiir, liy the limit iiri'iimiifi'roil from [liv cori'ralioiiiliiif; ciirwiii of iiriiiliirs of Coli'iliiisiioii lo siiiil iirimiirv iiir iii rfi@ iirimiirv rcifiiiiiriihiiu 7i.)

3. The herrin (lrfiriilmd promesa; iihirli coiiiiirisi ii ili'iift ciirrviit of iiil 'ml wit-er vario." :mil liwitoi'l :iir through .i hi-il of liiifl ol' illi'iitiir 1?:1l'iiiiigi rligiiiili iii :1 gus if'oiliiz'rr. mixing with the rvsliltiiig pro# 75 dover gm: 2willi-l iii' iiiil liiii-iiiii;v th@` gil; in :i f iriiii zv rmfii in :will iliriiliiigf the: rosiiiltilli iroiliifi: =-oiiiiii fon into tii'o f'iir roms, iirrlii A ,-iiroiiiliiry" :air lor coiiiliiistion iLl'i i roiliirer ofi liv the limit of 50 one of siiiil mi orcheiitirig priiiiiiiv :iir for ih@ Alriii I imi-li' of the iii'oiliiciir by @Xchange of limi, with the other olE said cur-- reiils. iiiiiil iiiiiodiicirig water i'niior into :i portion of ,rif primary nir current in which S5 Such limit exrhnriiio is occurring. mid tlierrfby mziintiiiiiioga iiitwrfen siirli portion of rho priniliry :iir mii-rrhh [mil the i-i'ii'iesii,finfliii fortiori of liv'. oi'iirirrioiiilirig iiroi'hwts of coiiiibiistion ciii'riint. fi relatively Qroiit (lii 9o ference of tcmoorfitiiiv. facilitating the ibstriic'lion of lient 'from auch products of immbiistioi.

4. The heroin rl comi zpassing ii il'irfifl profess i'cliioli kift mi 'rem ol mixe-,rl 95 :i fummo.l wr. iiil fliiiiliriff thi-i i'rsiilA lo( iiigg iiroil isi oi comlfiriitioii iiito tivo wir i0iits.ki.i1'f `f i wwimliiry iiir for rimiliiwtion will the iii'iioiiisor rw liv lhs) limit. of one o? ,Q l viirreri preli "ing iirirriiiri ziii for thi. irrii' izriiiiii ol' i'iii iiroiliirer hv lGb iixcliiiiii'i of h i with (lio oilior of Sfiiil currents. iii'iil irziimlziciiiiz Woher vapor jno ozirlv low triiiiiCiiitiirf`1 iiortion ol the priiimrv nir mirrrri. iii irhifli siivli lient QX- cl'ifiiigre is oroiirrinsz. and their-.hv niniiii'iiirr 110 iris hvtii'ecii siiirh portion iii' t' ii iniiirfif' :iii iiirrent. sind the, rorregriomlinif: portion o? (lie corresooniliiifr nrmli'skr oi riomliiiiton Ciirrrit, fi rvlsitiiolv gli-Pnt ilifleiriiiir@ oi" tpm. riori'tilro ifiirilitnting the :ii'iqti'iiriori of limit L15 from auch i'irofliicts'i of voii'ihi'sififiii curi-ont. 'The herein deSOrilii-iil vroom?. iilirli Comiiriqof iinqiiif! n (lf'iifi: riirrfirit of' iiimil iixitor i'fioor :owl liefitffii. nii' lirolsh :i liv l of fuel ol ell'iiffire gasif'ifiiig loi'illi in fi Iiis iiroili'crn mixing willi the remiltingf iroflor-rr Wis li-izifwl iiir arid burning 'lie gas iii :i fiiri'izicri rliiiiilivr. :intl (livifliiig the remit ing rirorliirm of corriliifstion into tiro viii*- i'onts. rirohoiiting .woconilsirv :iir for roiiiliii:- 125 lion with the nrmliicfr gioie bv li@ lia-,Qt of one of sziifl mirreiit iirfilifiiriiiig iiririiwii' oir l'oi' the rlizift siioiiv of lha rifoilifffi' iii @Xchange of lient with the other or Suhl wir. renta and iiifaporfftirigg 'water .in a portion of 130 the primary air current in which such heat exchange is occurring by the heat so communicated to the primary air, and thereby maintaining, between such portion of the primary air current, and the corresponding portion of the corresponding products of combustion current, a relatively great dif ference of temperature, facilitating the abstraction of heat from such products Ofcombustion.

G. rl`he herein described process which comprises passing a draft current of mixed water vapor and heated air through a bed of fuel of effective gasifyin depth in a gas producer, mixing with t e resulting producer gas heated air and burning the gas in a furnace chamber` and dividing the resulting products of combustion into two currents, preheating secondary air for combustion with-the producer gas by the heat of one of said currents, preheating primary air for the draft supply of the producer by exchange of heat with the other of said currents, and evaporating water in an early low temperature portion of the primary air current in which'such heat exchange is occurring, bv heat so communicated to the primary air, and thereby maintaining between such portion of the primary air current, and the corresponding portion of the corresponding products of combustion current, a relatively great difference of temperature facilitating the abstraction of heat from sifch products of combustion current and highly superheating the water vapor so carried bythe primary air current by heat transferred bythe 'early portion-ofthe corresponding current of products of combus tiontn 'such primary air current.

7 The herein described process which comprises passing a draft current of mixed water vapor and heated air through a bed of fuel of effective gasifying depth in a gas producer, mixing` with the resulting producer gas heated air and burning the gas in a furnace chamber, and dividing the resulting products of combustion into two cur rents, preheating secondary air for combus-4 :ion with the producer gas by the heat of one of said currents, preheating primary air for the draft supply of the producer by exchange of heat with the other of said currents, introducing water vapor to ay ortion of the primary air current in w ich such heat exchange is occurring, and regnlating the temperature and moisture-content,

of the' primary air, with respect to the characteristics of the fuel usedin the producer,

. by regulating the proportion to the primary air of tliewater vapor so supplied to such primary air.

8. The herein described process which comprises passing a draft current of mixed water vapor and heated air through a bed of fuel of effective gasifving depth in a gas producer, mixing with the resulting producer gas heated air, and burning the gas in a furnace chamber, and dividing the resultlng products of combustion into two currents, preheating secondary7 air for combustion with the producer gas by the heat of one of said currents, preheating priinarv air for the draft supply of the producer by exchange of heat with the other of said currents, and maintaining a substantially constant water-content in the primary air by supplying water to be evaporated to such primary air, during the exchange of heat between the primary air and the products of combustion, and permitting such pri mary air to evaporate so much of such moisture as it may.

9. The herein described process which comprises passing a draft current of mixed water vapor and heated air through a bed of fuel of effective gasifying depth in a gas producer, mixing with the resulting producer gas heated air, and burning the gas in a furnace chamber, and dividing the resulting products of combustion into two currents, preheating secondary air for combustion with the producer gas by the heat of one of said currents, preheating primary air for the draft supply of Athe producer by exchange of heat with the other `of said currents, and maintainingY a substantially constant water-content in the primary air by supplying water to be evaporated to an early low temperature portion of such primary air, during the exchange of heat between the primary air and the products of combustion, and permitting such primary air to evaporate so much of such moisture as it may.

10. The herein described process which comprises passing a draft current of mixed highly su erheated water vapor`and highly heated a'y through a bed of fuelA of effective gasifying depth in a gas producer, mingling with the resulting producer gas heated air and burning the gas in a furnace chamber, preheating air for the draft supply of the producer and mingling -water vapor with such draft supply after such air has been so heated to a considerable degree and highl)v superheating such water vapor by exchange of heat with products of comsiistrbn of the gas so burned in said furnace chamber.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

y HENRI L. DcHEaTY. 

